| Electronics > Beginners |
| How to protect buck output from backflow current from battery? |
| (1/1) |
| cbc02009:
Hello all, I'm still working on mppt controller, and I have another question that I can't seem to find an answer for on google. In my schematic, I have a p mosfet on the output of my buck converter to protect from reverse polarity (the gate is tied to ground), but I just realized that a p mosfet won't actually do anything to protect the circuit if the battery has a higher voltage potential than the charger, because Vgs will still be negative because of the voltage of the battery. I figure I could use a schottkey diode, but that's several watts of power loss. Is there a better solution that I'm missing? I'm surprised I can't seem to find anything about this issue online. I'm using a 12V 12ah SLA battery, if that matters. |
| T3sl4co1l:
How much load is on the buck input side? You can connect FETs in anti-series (i.e., gates together, sources together, wire drain-to-drain for load) for a bidirectional switch, of course it incurs twice the Rds(on), which makes P-ch MOS that much less desirable. There are protection controllers (reverse, UVLO, OVLO, surge) that handle this, if you want a one-chip solution (and don't mind paying for it). Tim |
| Navigation |
| Message Index |